Our ability to study the smallest components of our world took a giant leap forward when C.T.R. Wilson invented the cloud chamber, where the trails of charged particles can be observed. Donald Glaser's invention of the bubble chamber in 1952 made it possible to study particles with higher energies. When charged particles rush forward through the chamber filled with a liquid at near-boiling point, they ionize atoms they pass by. When the pressure inside the chamber is then reduced, bubbles form around these charged atoms. The particles' tracks can then be photographed and analyzed.